Belt conveyor frame and method for manufacturing the same

ABSTRACT

A belt conveyor frame and methods for manufacturing the same are disclosed, the cross section of the sidewall of the belt conveyor frame having at least two bends made thereto in two successive angles of opposite direction, whereby the sidewall cross section has essentially the shape of letter S or Z.

The invention relates to belt conveyors intended for transport of bulkmaterials.

In the prior art it has been conventional to construct a belt conveyorby welding or bolting the conveyor frame into an assembly comprising twosidewall elements that are fabricated by welding or bending and areconnected to each other by transverse members joining the sidewallelements. Conventionally, the sidewall element is fabricated by forminga trimmed length of sheet steel by shearing and bending into a sidewallcontinuous section whereto are attached, most usually by welding,stiffener plates compliant with the shape of the sidewall continuoussection in order to improve the stiffness of the sidewall element.

Conventionally, a continuous section used as the conveyor longitudinalsidewall is shaped so that each one of the successive bends are madeinto desired angles of the same direction so that the continuous sectionfinally assumes the shape of, e.g., letter C or G. In this context, theterm “same direction” must be understood to indicate that the successivebending angles in regard to the vertical plane of the continuous sectionare consistently either positive or respectively negative.

However, the bending shapes of conventional continuous sections arecomplicated by the problem that the installation of conveyor accessoriessuch as sidewall deckle, dust cover and hoses/piping therein iscumbersome, costly and time-consuming.

In prior-art conveyor constructions, the conveyor accessories mounted onthe conveyor frame are generally fastened with screws. However,conventional conveyor constructions conceal simultaneous access to bothsides of the screw connection thus making it impossible to prevent thescrew or nut, respectively, from turning while its counterpart is beingunscrewed or tightened. Attempts to overcome this problem have been madeeither by machining inner threaded holes to the conveyor sidewall at theintended fastening points of accessories or by attaching screws or nutsto the sidewall during its fabrication by welding, for instance. Both ofthe above alternatives are costly and work-intensive. Furthermore,additional welds made on the sidewall degrade the wear resistance of thesidewall.

Further known in the art is the use of special screws or nuts for fixingconveyor accessories. Obviously, these fixtures are more expensive thanconventional components and, additionally, need additional working ofthe sidewall so that the continuous section is machined to includerecesses or notches suitable to hold the special fixtures in place. Alsosuch recesses and notches are costly and time-consuming to fabricate.Moreover, the recesses/notches deteriorate the wear resistance of thesidewall.

The above-described constructions cause many kinds of complications inthe manufacture and service of conveyors.

In order to overcome the above disadvantages, a novel conveyor frameconstruction and method for manufacturing the same are now disclosed. Inaccordance with the present invention, the conveyor frame sidewall ismade from a continuous section having a substantially S- or Z-shapedcross section.

The benefits of the present invention include easy and rapid mounting ofconveyor accessories. Furthermore, the construction according to theinvention is inexpensive, stiff and more durable under wearing stress.

More specifically, the belt conveyor frame according to the invention ischaracterized by what is stated in the characterizing part of claim 1and the manufacturing methods of the belt conveyor frame according tothe invention is characterized by what is stated in the characterizingparts of claims 3, 4, 5 and 6.

In the following, the invention is described in more detail by makingreference to the appended drawings, in which

FIG. 1 shows a mineral material processing unit equipped with a typicalbelt conveyor;

FIG. 2 shows a side elevation view of a typical belt conveyor employedin the transfer of bulk materials;

FIG. 3 shows a cross section of a typical belt conveyor;

FIG. 4 shows an enlarged view of a detail of the belt conveyor of FIG.3;

FIG. 5 shows a detail of a continuous section of a belt conveyorequipped with notches suitable for accommodating a special screw;

FIG. 6 shows a cross section of a belt conveyor construction accordingto the invention;

FIG. 7 shows an enlarged view of the sidewall structure of the beltconveyor of FIG. 6 according to the invention; and

FIG. 8 shows an exemplary embodiment of the manufacturing method of thesidewall continuous section of a belt conveyor frame according to theinvention.

Referring to FIG. 1, therein is shown a mineral material processing unitequipped with a belt conveyor 1. This kind of processing unit may be,e.g., a feeder, crusher or screening unit.

In the belt conveyor 1 shown in FIG. 2 typically suited for thetransport of bulk materials such as crushed rock, the main componentsare a conveyor frame 2, a driven head pulley 3, a tail pulley 4 and aconveyor belt 5. Conventionally, the conveyor belt 5 is adapted to runas an endless loop about the head pulley 3 and the tail pulley 4 mountedin bearings at the ends of the conveyor frame 2, whereby the belt isdriven by head pulley. The loaded leg of the belt is additionally backedby support rollers mounted at a suitable distance from each other in theconveyor frame 2. Under the conveyor frame, facing the return leg of thebelt, are generally mounted support rollers known as jockey rollersserving to support the belt return.

The conveyor frame 2 may comprise plural modular frame elementsconnected to end-to-end with each other, either permanently ordetachably. The modular frame elements may also be connected with eachother in a fashion permitting connection of the modular elements with abend/angle therebetween.

FIG. 3 shows the cross section of a typical belt conveyor perpendicularto the longitudinal axis of the conveyor. Hanging between the sidewalls6 of the conveyor frame is mounted a modular roller set comprising beltsupport rollers 8, 9, 9′ adapted rotary on a cable 10 or a pivotallylinked support shaft such that the cable 10 or the pivotally linkedshaft is passed through each one of the support rollers at the rollercenter axis. The conveyor belt 5 running on the support rollers forms atrough on which the bulk material travels during the operation of theconveyor.

Along its return leg, belt 5 is supported by support roller set 12.

The cable 10 or the pivotally linked shaft on which the support rollers8, 9, 9′ rotate is generally shaped such that its ends are provided witheylets insertable into slots made to the sidewalls 6 of the conveyorframe or lockable to the conveyor frame with wedges 11. This arrangementpermits easy and fast installation of the conveyor roller set to theconveyor frame.

Conventionally, the conveyor is also equipped with certain accessoriessuch as a side panel apron 13 and a dust cover 15. The function of theside panel apron is to prevent bulk material from falling off from theconveyor belt 5 via the gap between the conveyor belt and the sidewall 6of the conveyor frame. The dust cover 15 serves to enclose the possiblydusty bulk material inside the conveyor so that the dust emissionscannot escape to the surroundings. The conveyor may further becomplemented with, e.g., a dust vacuuming manifold/piping or a waterspraying manifold/piping that either replaces or complements thefunction of the dust cover. Both of such installations aim at reductionof environmental load due to emissions from dusty bulk materials.

The side panel apron 13 and dust cover 15, as well as other accessories,are generally fixed in place with screws 14, 16.

FIG. 4 shows in an enlarged view a detail of the belt conveyor of FIG.3. As is evident from the diagram, the conveyor frame sidewall 6 iscomprised of a continuous section 17 and a stiffener plate 18. Thepre-engineered sidewall is fastened to cross members 7, whereby theconveyor frame 2 is formed.

The continuous section of the conveyor frame sidewall is made from sheetsteel by shearing and bending. In the exemplary embodiment shown in thediagram, the sidewall continuous section 17 can be said to essentiallyresemble letter C, whereby the sheet is bent so as to conceal thesidewall stiffener plate 18 in a view taken from the side and top of theconveyor frame and also a portion of the conveyor frame remainsconcealed in a view taken from inside the conveyor frame. The continuoussection may additional be bent so that it conceals the sidewallstiffener plate at least partially when the conveyor frame is viewedfrom below. If reasons related to manufacture or visual look of theconveyor so urge, the number of bends may be increased to give thecontinuous section a shape essentially resembling letter G, forinstance. In its simplest form, the cross section of the continuoussection may be shaped as letter J or L.

The screw connections 14, 16 fastening the accessories may be formed byway of, e.g., machining to the conveyor frame 6 an inner-threaded holethat in the mounting of accessories 13, 15 accommodates tightening ascrew thereto. In lieu of a threaded hole, the conveyor frame may beprovided with holes having nuts attached thereto by welding, forinstance, whereby in the mounting of accessories a screw of the samethread size as that of the nut attached into the hole is tightenedthereto. The screw connections fastening the accessories may also beimplemented by way of attaching to the conveyor frame anexternally-threaded member that can be passed through a hole made in theaccessory whereupon a nut can be tightened on the externally-threadedmember. The externally-threaded member fixed to the conveyor frame maybe, e.g., a bolt or a length of threaded rod fastened by welding.

In certain cases in lieu of the inner-threaded bolt/hole made on thecontinuous section 17 of the conveyor frame sidewall 6 for mountingaccessories 13, 15, a special type of screw or nut (not shown) may beused, whereby the continuous section of the conveyor frame sidewall mustbe provided with a keyhole 19 shaped to accommodate the keybase of sucha special screw/nut thus locking the threaded component in a nonrotaryfashion to the conveyor frame. A continuous section 17 with keyholes 19suited for this purpose is shown in FIG. 5.

In FIG. 6 is shown the cross section of a belt conveyor constructionaccording to the invention taken perpendicular to the longitudinal axisof the conveyor, while in FIG. 7 is shown an enlarged view of the beltconveyor sidewall structure of FIG. 6 and fastening of the sidewall to across member of the conveyor frame.

In FIGS. 6 and 7 are identifiable the same members as those used in theconventional conveyors of FIGS. 4 and 5 discussed above. However, herethe characteristic feature of the conveyor construction according to theinvention is the novel construction of a conveyor frame sidewall 20.

In the conveyor construction according to the invention, the conveyorframe sidewall 20 is formed by way of fabricating a sidewall continuoussection 21 through shearing and bending a sheet steel plate in at leasttwo different direction so as to obtain the essentially letter S- orZ-shaped cross section of the sidewall continuous section 21. In thiscontext the meaning of two different direction is that the sheet bendingangle relative to the vertical plane of the continuous section variesbetween a positive and a negative angle. This kind of shape is partiallyopen and partially closed in a view taken on the sidewall continuoussection 21 from both inner side and outer side of the conveyor frame.

Most advantageously, a stiffener plate 22 of the sidewall 20 is madefrom two parts 22 and 22′, whereby the structure becomes very stiffagainst both bending and torsional stresses imposed on the sidewall.

In addition to the strength and stiffness of the sidewall constructionaccording to the invention, it also offers uncomplicated mounting ofconveyor accessories. After the conveyor frame 2 is equipped withappropriate support rollers 8, 9, 9′ and belts 5, the sidewall apron 13can still be easily mounted and dismounted inasmuch as both sides of thescrew connection 14 are visible and easily accessible with tools fromthe external side of the conveyor frame. Also the dust cover 15 is easyto mount and dismount, since both sides of the screw connection 16 areas well visible and easily accessible with tools from the external sideof the conveyor frame.

FIG. 8 shows an exemplary embodiment of the manufacturing method of thecontinuous section of the belt conveyor sidewall, now having thesidewall continuous section drawn in a coordinate system. In themanufacturing method, the blank of the sidewall continuous section isfirst bent in a direction that forms a positive angle α relative to theplanar portion of the continuous section that is aligned parallel to thevertical axis of the coordinate system. In the second step ofmanufacture, the plate of the continuous section is bent in a directionthat forms a negative angle β relative to the plane of the first bentportion. By bending the blank of the continuous section in this fashionin two angles opposite to each other, the continuous section finallyassumes a shape having a cross section essentially resembling letter Sor Z. While in the exemplary embodiment shown in the diagram, angle axis about 45° and angle β is about 90°, the implementation of theinvention is not limited to the use of the bending angles mentioned inthis example.

In the context of this description, the definitions of negative andpositive angle are the same as those conventionally used for the anglesof a unit circle in trigonometry.

In the exemplary embodiment of FIG. 8, the bending of the continuoussection blank into the desired shape of its cross section is shown totake place in two steps. Obviously, the bends may as well be made in asingle step. The continuous section can be fabricated by shearing ablank and then bending it stepwise in different angles or,alternatively, the blank may be machined in a single step using suitablepress tools, possibly combined with shear tools, so that all the bendsof the continuous section are formed by a single stroke of a bendingpress. Obviously, the invention is not limited to a given order offorming the angles of the cross section of the continuous section. Whennecessary, the press may be complemented with a shear tool such that thecontinuous section is separated from the raw material sheet at the sametime as the press stroke makes the required bends.

The cross section of the sidewall continuous section may also be shapedwith plural bends at desired angles in the fashion shown in theexemplary embodiment of FIG. 8. Even herein, an essential feature of theinvention is that at least a major portion of the cross section of thecontinuous section shall assume essentially the shape of letter S or Z,whereby at least two successive bends must be made at angles opposite toeach other in the manner disclosed in the appended claims.

The continuous section of the conveyor sidewall according to theinvention may also be fabricated by die extrusion using a die with anexit opening substantially equal in shape to the desired cross sectionof the sidewall continuous section, whereupon the raw material of thecontinuous section, e.g., aluminum, can be extruded through the die andallowed to cool thus forming the sidewall continuous section accordingto the invention.

Still further, the sidewall continuous section according to theinvention may alternatively be fabricated by combining several basiccontinuous sections, which may be either flat or bent by their crosssection, into the sidewall continuous section according to theinvention. Such simple continuous sections can be joined to each otherby welding, for instance.

Since the mounting of accessories on the conveyor sidewall constructionaccording to the invention can be carried out using standard screws andnuts, there is no need for the use of expensive special screws and/ornuts. Furthermore, since no recesses or slots need be made on thepresent kind of conveyor sidewall, the conveyor frame is less costly tomanufacture and offers improved resistance to wear.

As the invention is not limited to any specific material of the conveyorframe, also other materials than steel may be used in the manufacture ofthe frame structure.

Still further, the conveyor frame may comprise a single length of thesidewall continuous section or, alternatively, the frame can beassembled from plural separate modular sidewall units so that a conveyorframe longer than a single modular sidewall unit results.

Neither is the invention limited to any specific assembly method of theconveyor frame, but rather, the frame components can be connected toeach other by welding or using other conventionally employed fasteningmethods.

Besides screw connections, the mounting of accessories may beaccomplished using other connection methods known in the art.

1. A belt conveyor frame, wherein the sidewall continuous section of thebelt conveyor frame supports a modular roller set that in turn supportsa conveyor belt in a manner which forms the conveyor belt into a troughsuitable for transport of bulk material, characterized in that the crosssection of the continuous section used in the conveyor frame sidewall isshaped to include at least two successive bends, each of them being madeat an angle opposite to the adjacent bend, thus rendering the crosssection substantially the shape of letter S or Z.
 2. The belt conveyorframe of claim 1, characterized in that the sidewall continuous sectionof the belt conveyor frame is comprised of two or more lengths ofmodular continuous section connected end-to-end with each other.
 3. Amethod of manufacturing the sidewall continuous section of the beltconveyor frame of claim 1, characterized in that the sidewall continuoussection is made from sheet material by bending.
 4. A method ofmanufacturing the sidewall continuous section of the belt conveyor frameof claim 1, characterized in that the sidewall continuous section ismade by joining several simple continuous sections to each other.
 5. Amethod of manufacturing the sidewall continuous section of the beltconveyor frame of claim 1, characterized in that the sidewall continuoussection is made by extrusion.
 6. A method of manufacturing the sidewallcontinuous section of the belt conveyor frame of claim 1, characterizedin that the sidewall continuous section is made from sheet material bypressing.